Lubricating compositions



Patented Aug. 4, 1953 LUBRICATING COMPOSITIONS John Bryant Matthews and Thomas Bevan Grimshaw, Cheshire, England, assignors to Shell Development Company, San Francisco, Calif., a

corporation of Delaware No Drawing. Applicatio May 17, 1949, Serial No. 93,847. In Great Britain July 7, 1948 7 Claims. 1

This invention relates to improved lubricants and to a process for their preparation. More particularly, the invention pertains to the prep aration of a novel class of compounds which are especially suitable as additional agents to lubrieating oils and greases. In one of its more specific embodiments, the invention covers a process for the preparation of certain compounds which, when added to base lubricants, such as natural and/or synthetic lubricating oils, materially improve their properties, particularly when such compounded oils are used for the lubrication of engines operating under adverse conditions, such as under extreme pressures and/or elevated temperatures, or under low temperature conditions, or in the presence of high-sulfur fuels, contaminants, e. g. water, corrosive acids, and the like.

It is well known that substantially stable base oils tend to deteriorate under conditions ofengine use, forming deterioration products which cause corrosion of engine parts, ring-sticking, sludging, wearing of engine parts, and general fouling of the engine system. This tendency of the oil to deteriorate is increased or, accelerated by an elevation of the ope ating temperature, by traces of impurities which act as pro-oxidants, by degradation products present or formed in the oil and/or the fuel, such as water, corrosive acids, sulfur oxides, sulfurous acid, carbon dioxide, etc.

It is common practice toadd, d Qfb d, into such base oils and lubricants, various additives which inhibit deterioration of base: oils, aid in preventing engine wear, and act as-detergents, thereby assisting in theqremoval of sludge or other deleterious matter, such as mentioned above; also these additives. may be capable of imparting certain desirable properties such as corrosion inhibition, as well as anti-rusting and extreme pressure properties, thus rendering them more useful in greater fields of application.

One of the chief drawbacks of oil additives in general is their short period of effectiveness. Thus, for example, compounded oils for use in engines, on extended use, progressively decrease in eiiectiveness, and in many cases fail to function completely, due to decomposition, depletion and/or chemical reaction associated with their inhibiting effect. Since it is extremely diflicult or at times impossible to replenish the base oil with a desired additive agent, the efiectiveness oi a compounded oil becomes limited and presents a serious problem where effective continuous inbrication for extended periods of time is required. Another drawback of oil additives. is that generally they are mono-functional and therefore if an improved compounded lubricant is desired, use

2 of a plurality of additives is a necessity which practice, generally causes interference of the additionwith each other, if not selected with great care.

It is an object of this invention to obviate the aboveand other defects, and to provide a novel class, of products or compounds, which on addition to a base lubricant imparts excellent lubricating properties to it for extended periods of time. It is a further object of this invention to prepare a lubricating oil additive which resists decomposition and is not readily depleted during use. It is another object of this invention to prepare an oil additive which is resistant to hydrolysis and corrosive agents, e. g. water, sulfur oxides which may be present or formed in the base oils. It is still another object of this invention to prepare an oil additive having multifunctional prcper'ties such as detergent and anticorrosion and rust-inhibiting properties. A further object of this invention is to provide a noncorrosive lubricating composition having excellent detergent properties. These and other objects of this invention will be apparent from the following description and appended claims.

It has now been discovered that theaboveand other objects may be attained by forming the salts of condensation products of this invention as hereinbelow defined in a single stage process, and, if desired, in the presence of a suitable carrier, and thereafter subjecting the salt thus formed to a heat treatment at an elevated temperature for a more or less prolonged period of time, and with or without agitation. Furthermore, it has been discovered that products formed by the process of this invention are totally different from the similar products produced by processes known in the art and that the products of this invention have wide applicability lubricants, fuels, detergents, rubber compositions and the like. The ingredients which may be used to form the metal salts of condensation products of this invention are as follows:

(1) An aromatic compound containing a polar radical or radicals, which compound can be represented by the general formula:

where Ar is a mono or polynuclear aromatic ring, R is an alkyl, alkoxy, aroxy or aryalkyl radical, having attached thereto, if desired, one or more polar groups, m is'an' integer of from 1 t 3, B. is a hydrocarbon radical having a plurality of carbon atoms and, if desired, having attached thereto one or more polar groups, 1'1 may be or 1' X is a polar group having a reactive hydrogen, and q is an integer of at least one. When q is more than one, such as two or three,

X may be a plurality of polar groups at least one of which must have a reactive hydrogen. The polar radicals may be OH, Cl, Br, CN, NHz, N02, NO, N NO, 0001-1, and the like, provided at least one of the X radicals in the above formula should have replaceable hydrogen. Compounds illustrative of the above general formula, and which may be used to form the condensation reaction products with aldehydes, are: dibutyl phenol, amylphenol, ditertiary butyl phenol, octyl phenol, p-isoctyl phenol, isobutyl phenol, nonyl phenol, cetyl phenol, alkyl amino naphthol; alkyl cinnamyl alcohol, methyl phenyl carbinol, octyl nitrophenol, octyl nitroso phenol, amino butyl nitro phenol, octyl benzenediol, alkyl salicylic acid, etc.

(2) The aldehydes which can be used to form condensation products with the above-mentioned aromatic compounds can be aliphatic aldehydes, such as formaldehyde, acetaldehyde, crotonaldehyde, butyraldehyde, furaldehyde and the like.

A lower molecular aldehyde such as formaldehyde or acetaldehyde is preferable in forming the condensation products of this invention. The condensation of such aldehydes with phenols, for example, preferably having an alkyl, cycloalkyl or aryl group which is ortho to the hydroxy group, may be carried out by any well known process, for example, by heating with an acid or basic catalyst. Depending upon starting materials and condensation conditions the products vary in appearance from viscous liquids to resinous materials. A number of such condensation products are commercially available, and since their methods of manufacture are generally known, further details regarding such manufacture will not be recounted here. However, U. S. Patent 2,250,188 is mentioned as a reference for disclosing a method for preparing a condensation product which can be used as a component in compositions of this invention.

To form the final desired product in a single process, the above two essential materials are simultaneously reacted with a basic metallic compound, such as the metallic oxides, hydroxide or carbonates. Although any basic metallic compound may be used for this neutralization, it is preferred to use those compounds which leave a polyvalent metal. Of these, the alkaline earth metals are generally preferred, although other polyvalent metals, such as Zn, Cd, Pb, Fe, Ni, Co, Cu, Cr and Sn, may also be employed.

The heat treatment of the products resulting from the single stage process should be effected in the presence of a substantially non-polar liquid. Also, the formation of these salts by the single stage process is prefer-ably effected in the presence of such a substantially non-polar liquid. It is preferable to employ as such medium a fluid which is stable at the elevated temperatures employed during the preparation of the condensation product and its subsequent heat treatment, so that said medium does not decompose -to any substantial degree at such temperatures. Also, in some instances, particularly when it is desired to separate the desired reaction product from such fluid medium, it is preferable, if not essential, to employ as the diluent or solvent, a fluid which may be readily separated from the reaction product, e. g. by distillation at ordinary or subatmospheric pressure. Although the conversion according to the process of the present invention of the metal salts may be effected in the presence of any substantially nonpolar fluid in which the salt is soluble or dispersible, it is generally preferable to employ, as such fluid, a hydrocarbon fraction which, as stated, does not decompose to any substantial degree at the elevated temperatures employed in the decomposition step. For instance, the highly refined oils, such as, paraflinic hydrocarbon fractions or medicinal oils, may be used. The conversion may also be effected in the presence of mineral lubricating oils, particularly when the resulting mixture is to be used as such lubricant or is to be diluted with additional amounts of the same or other lubricating oils. If desired, the mineral oil may be removed from the reaction product of the metal salt, for instance by high vacuum distillation, which leaves the reaction product in the form of a solid substance. When the product has been prepared in a medium of a substantially non-polar fluid other than a mineral lubricating oil, which fluid may be a high molecular weight ether, such as di-n-dodecyl ether, and when it is desired to obtain the substance from such fluid for use as such or for the purpose of adding it to .a mineral lubricating oil fraction, it is then possible to separate the fluid medium in part or completely, e. g. by distillation, and to use the resulting solid substance as the anti-ring sticking agent or additional product to mineral lubricating oils.

Broadly stated, the process of this invention may be carried out as follows: A desired alkylsubstituted aromatic containing a polar group having a replaceable hydrogen compound, such as alkylated phenol, and a neutralizing agent, is dissolved in a solvent and, while this mixture is being heated to 50-l00 C., an aldehyde is added quickly in a desired molar ratio. The molar ratio of the aldehyde to the alkylated aryl-containing polar compound may vary from about 0.9 to about 2.0 and generally an excess of about of the neutralizing agent is used. The reaction starts almost immediately as is generally noted by the color changes which takes Place; the reaction is generally carried out at a temperature ranging from about C. to about 150 C. At the conclusion of the desired reaction time, which may vary from a fraction of an hour to over 20 hours, excess neutralizing agent and the solvent are removed by any suitable means after subjecting the condensation product thus formed to a heat treatment. This heat treatment of condensation products of this invention is effected at temperatures ranging from 100 C. to 250 C., and preferably at 120 C. to 160 C. for from one half to 50 hours.

To more clearly illustrate the present invention, the following examples are presented. It is to be understood, however, that various modifications can be resorted to without departing from the spirit of the invention.

EXAMPLE I About 496 parts of para-octyl phenol, 2,200 parts of a solvent-refined mineral lubrication oil, and 100 parts of calcium hydroxide, were heated together to about C. to C., and 240 parts of a 40 per cent aqueou formaldehyde solution was then added. This mixture was heated for about three hours under reflux, the temperature being raised to 85 C. over the period. The above condensation product was air-blown for about one hour at from C. to C., and then heat treated for over one hour at a temperature of from C. to C. This heat-treated product was flltered while hot under a reduced pressure to yield a concentrate having a'sulfated Approximately equal molar quantities of 4- octyl phenol and lime were dissolved in about 80% of a solvent (mineral oil), andthe mixture was heated to 50 C.-60 C. The required amount of formaldehyde to givethe desired molar ratio was then added quickly. The reaction started immediately, as was evidenced by a color change from white to a lemon yellow, which took place in from 5 to minutes. Thereaction was continued at a temperature of from 50 C. to 75 C., for over one hour, and the resulting condensation product showed that it contained 1.44% sulfated ash.

A 20% concentration in mineral oil of the above condensation product was heat-treated by p longed heating at a temperature of from 120 C. to about 170 C. under constant agitation until the condensation product became permanently discolored. Within the lower temperature range of 120 C. to 135 C. this permanent discoloration which is a darkening in color of the reaction product from a white to a green or greenish-blue, takes from to hours, whereas at the more elevated temperatures of 160 C. to 170 C. the discoloration takes place in about 5 hours.

EXAMPLE III The following ingredients were admixed and reacted in the manner described in the previous examples.

Octyl phenol 60 Petroleum solvent 260 Paraformaldehyde 10.1 Lime 9.7

Water 1 Prior to heat-treating the product a'portion of it was removed and was extremely viscous-when hot and semi-solid when cold. The remainder of the reaction product was heated for 160 C. for two to three hours, with stirring and the two materials were subjected to the hydrolysis test as described hereinbelow and the sulfated ash of each material was also determined.

EXAMPLE IV The non-heat treated and the heat-treated salts of Example III were prepared in the same manner as above except that the amount of octyl phenol used was halved. The products were ashed and subjected to the hydrolysis depletion test and the results were as follows:

Ca octyl phenol-aldehyde condensation product prior to heat treatment:

Sulfated ash 2.68% wt.

Depletion in hydrolysis test 100% wt. Heat-treated Ca octyl phenol-formaldehyde condensation product:

Sulfated ash 3.79% Depletion inhydrolysis :test.40t%

The effect of stirring the condensation product during its heat treatment has a remarkable effect upon its stability and resistance toward hydrolysis. Therefore, where an extremely stable product is desired, it is advisable to conduct the heat treatment of products of this invention under conditions of'agitation.

Other typical examples ofheat-treated condensation products of this invention which also show an appropriateash increase over similar products which. have not been heat treated and which are more. stableand resist hydrolysis are the heat treated Ca, Mg, Sr, Cu, Zn, Al and Sn salts of the condensation products of:

.diisobutyl nitrosophenol formaldehyde condensation product diisobutyl cyano phenol formaldehyde condensation product diisobutyl phenol sulfonic acid formaldehyde condensation product When used as additives to lubricating oils, these heat-treated condensation products or mixtures thereof may be used in amounts varying from 0.01% to 5%, and generally are to be used in amounts ranging from 0.1% to 2% by weight. However, amounts as high as 20% by weight can be used.

To illustrate the pronounced improvement obtained when additives of this invention are added to an oil base the following test data is given:

Test procedure Condensation products prepared in the manner as described and identified hereinbelow were subjected to the followingtest:

Separate samples of about 50 grams each of compositions A, B and C were tested in a reciprocating wear machine and the results are summarized below:

Materials 4K6 cast iron slider, mean roughness 4-6 micro-inches. Nitralloy plate, mean roughness 2-2 microinches.

Conditions:

Speed v800 R.P. M. Temperature C. Load 40 lb. Stroke 12cm.

condensation;

Two samples of Ca salt of octyl phenol-formaldehyde were prepared in accordance with the teaching of the present invention but (a) sample was heat-treated at 130 C. for 14 hours with constant stirring while (b) was heat-treated under the same conditions but without stirring and each sample was mixed with 1% of water and shaken in an atmosphere of carbon dioxide for 6 hours at room temperature, the carbon dioxide atmosphere being renewed at /2 hour intervals. After this treatment the mixture is filtered through a Sterimat filter and the sulfated ash is a measure of the additive depletion and hence of the stability of the additive to water and carbon dioxide. By this means it is possible to determine when a lubricating oil composition has become substantially stable to weak acids. The per cent additive depletion was observed.

Composition A-Heattreatcd Example I Composition BNon-heat-treated Example I Composition CCa salt of octyl phenolf-ormaldehyde condensation prepared in the conventional manner by first condensing octyl phenol with formaldehyde and then neutralizing with lime.

Comparative hydrolysis stability measurements Additive Composition Depletion (Percent) Composition A 8 Composition B 100 Composition C l. 28

Additive depletion Percent Composition (A) (stirred) 1 Composition (A) (no stirring) 16 Compositions A, B and C were also compared for their detergent, anti-rusting properties and stability to weak acids. The results are tabulated below:

Detergent Anti-Busting Stability to Properties Properties Weak Acid Composition A Very good", Fair Very good. CompositionB "do Good Very bad. Composition C do Bad Good.

The heat-treated condensation products of this invention can be combined with other additives in lubricants, such as blooming agents, pourpoint depressants or viscosity improvers, extreme pressure agents, anti-foaming agents and the like. Among the specific additives which can be usedare oil-soluble salts of various bases with detergent-forming acids. Such bases include metal as well as organic bases. Metallic bases include those of alkali metals, Cu, Mg, Ca, Sr, Ba, Zn, Cd, A1, Sn, Pb, Cr, Mn, Fe, Ni, Co, etc. Organic bases include various nitrogen bases as primary, secondary, tertiary and quaternary amines.

Examples of detergent-forming acids are the various fatty acids of say 10 to 30 carbon atoms, wool fat acids, paraflin wax acids (produced by oxidation of paraffin wax), chlorinated fatty acids, rosin acids, aromatic carboxylic acids, including aromatic fatty acids, aromatic hydroxy fatty acids, paraffin wax benzoic acids, various alkyl salicyclic acids, phthalic acid mono-esters, aromatic keto acids, aromatic ether acids, diphenols as di(alkylphenol) sulfides and disulfides, sulfonic acids such as may be produced by treatment of alkyl aryl hydrocarbons or high-boiling petroleum oils with sulfuric acid; sulfuric acid mono-esters; phosphoric, arsonic and antimony acid mono and diesters, including the corresponding thiophosphoric, arsonic, antimony, phosphonic acids and the like.

Additional detergents are the alkaline earth phosphate diesters, including the thiophosphate diesters; the alkaline earth diphenolates, specifically the calcium and barium salts of diphenol mono and polysulfides.

Non-metallic detergents include components such as the phosphatides such as lecithin and cephalin, certain fatty oils as rapeseed oils, volatilized fatty or mineral oils and the like.

An excellent metallic detergent for the present purpose is the calcium salt of oil-soluble petroleum sulfonic acids. This may be present advantageously in the amount of about 0.025% to 0.2% sulfate ash.

Corrosion inhibitors or anti-rusting compounds may also be present such as dicarboxylic acids of 16 and more carbon atoms; alkali metal and alkaline earth salts of sulfonic acids and fatty acids; organic compounds containing an acidic radical in close proximity to a nitrile, nitro or nitroso group (e. g. alpha-cyano stearic acid).

Extreme pressure agents which may be used comprise: esters or phosphorus acids such as triaryl, alkyl hydroxy aryl, or aralkyl phosphates, thiophospha-tes or phosphites and the like; neutral aromatic sulfur compounds of relatively high-boiling temperatures such as diaryl sulfides, diaryl disulfides, alkyl aryl disulfides, e. g. diphenyl sulfide, diphenol sulfide, dicresol sulfide, dixylenol sulfide, methyl butyl diphenol sulfide, dibenzyl sulfide, corresponding diand trisulfides, and the like; sulfurized fatty oils or esters of fatty acids and monohydric alcohols, e. g. sperm oil, jojoba oil, etc., in which the sulfur is strongly bonded, sulfurized long-chain olefins such as may be obtained by dehydrogenation or cracking of wax; sulfurized phosphorized fatty oils or acids, phosphorus acid esters having sulfurized organic radicals, such as esters of phosphorous or phosphoric acids with sulfurized hydroxy fatty acids; chlorinated hydrocarbons, such as chlorinated paraffin, aromatic hydrocarbons, terpenes, mineral lubricating oil, etc., or chlorinated esters of fatty acids containing the chlorine other than in the alpha position.

Additional ingredients may comprise oil-soluble urea or thiourea derivatives, e. g. urethanes, allophanates, earbazides, carbazones, etc., polyisobutylene polymers, unsaturated polymerized esters of fatty acids and monohydric alcohols and 9 other high molecular weight oil-soluble compounds.

Depending upon the additive used and conditions under which it is used, the amount of additive used may vary from 0.01% to 2% or higher. However, substantial improvement is obtained by using amounts ranging from 0.1% to 0.5% in combination with the two primary additives of this invention.

Compositions of this invention may be used with motor oils, turbine oils, steam cylinder oils, marine engine oils, refrigeration oils, and used for various lubricating purposes other than engine lubrication such as slushing and flushing oils, rust inhibiting oils, quenching and drawing oils, greases, wax compositions, and the like.

We claim as our invention:

1. A process for preparing an improved oil additive comprising heating about equal molar proportions of p-octyl phenol and lime in a, refined mineral lubricating oil to about 60-65 C., adding thereto about an equal molar proportion of formaldehyde and heating the reaction mixture at a temperature of from 50 C. to 75 C. whereby a calcium salt of the p-octyl phenol-formaldehyde condensation product is formed and thereafter heat treating said salt at a temperature of about 160 C. to 170 C. for a period of time of about 5 hours.

2. A process for preparing an improved oil additive comprising condensing octyl phenol with formaldehyde and simultaneously neutralizing with lime and thereafter heat-treating said condensation product at a temperature of from 100 C. to 250 C. for a period of time between onehalf and fifty hours.

3. A process for preparing an improved oil additive comprising condensing an alkyl phenol with an aliphatic aldehyde, said aldehyde having no more than four carbon atoms per molecule and simultaneously neutralizing said condensation product with an alkaline earth metal basic compound, and thereafter heat-treating said neutralized condensation product at a temperature of from 120 C. to 170 C. for a period of time between one-half and fifty hours.

4. A process for preparing an improved oil additive comprising heating an alkyl phenol and an alkaline earth metal basic compound in a solvent to a temperature between 50 and 100 0., adding thereto an aliphatic aldehyde, said aldehyde contalning no more than four carbon atoms per molecule, in a molar ratio of aldehyde to phenol of between about 0.9 and 2.0, heating the reaction mixture to a temperature between about C. and 150 C. whereby a salt of the condensation product of said phenol and aldehyde is formed and thereafter heat-treating said salt at a temperature between C. and 170 C. for a period of time between one-half and fifty hours.

5. A process for preparing an improved oil additive comprising condensing an alkyl phenol with an aliphatic aldehyde, said aldehyde having no more than four carbon atoms per molecule and simultaneously neutralizing said condensation product with an alkaline earth metal basic compound, and thereafter heat-treating said neutralized condensation productv at a temperature of from 120 C. to C. for a period of time between 15 and 20 hours.

6. A process for preparing an improved oil additive comprising condensing an alkyl phenol with an aliphatic aldehyde, said aldehyde having no more than four carbon atoms per molecule and simultaneously neutralizing said condensation product with an alkaline earth metal basic compound, and thereafter heat-treating said neutralized condensation product at a temperature of from C. to C. for a period of time of about five hours.

7. A process for preparing an improved oil additive comprising condensing an alkyl phenol with an aliphatic aldehyde, said aldehyde having no more than four carbon atoms per molecule and simultaneously neutralizing said condensation product with an alkaline earth metal basic compound, and thereafter heat-treating said neutralized condensation product at a temperature of from 100 C. to 250 C. for a period of time between one-half and fifty hours.

JOHN BRYANT MATTHEWS. THOMAS BEVAN GRIMSHAW.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,250,188 Wilson July 21, 1941 2,280,419 Wilson Apr. 21, 1942 2,375,222 Griffln May 8, 1945 2,399,877 McNab May 7, 1946 

3. A PROCESS FOR PREPARING AN IMPROVED OIL ADDITIVE COMPRISING CONDENSING AN ALKYL PHENOL WITH AN ALIPHATIC ALDEHYDE, SAID ALDEHYDE HAVING NO MORE THAN FOUR CARBON ATOMS PER MOLECULE AND SIMULTANEOUSLY NEUTRALIZING SAID CONDENSATION PRODUCT WITH AN ALKALINE EARTH METAL BASIC COMPOUND, AND THEREAFTER HEAT-TREATING SAID NEUTRALIZED CONDENSATION PRODUCT AT A TEMPERATURE OF FROM 120* C. 170* C. FOR A PERIOD OF TIME BETWEEN ONE-HALF AND FIFTY HOURS. 